This disclosure is directed to a process to convert polymers into completed products which are electrically conductive across the surface. More particularly, the present procedure accomplishes conversion of polymeric surfaces into a conductive surface at milder conditions and in shorter treatment times during the practice of the improved process of this disclosure. Perhaps a definition of various electrical conductivities will assist in identifying benefits of the present process. In general terms, a material which has an electrical conductivity of 10.sup.-15 /ohm cm is defined as an insulator. Any material which is less conductive of this can be treated as an insulator material. Where the conductivity is typically in the range of about 10.sup.-6 to about 10.sup.-9, an antistatic material is provided. An EMI shielding polymer typically will have a conductivity of about the range of 10.sup.-2 to about 10.sup.-6. A conductivity of about 1 is typical of silicon and the conductivity of graphite is about 10.sup.6. Conductive metals such as silver and copper typically have a conductivity of about 10.sup.9. The present procedure enables manufacture of polymer materials which, subject to control of the process, can yield antistatic materials or EMI shielding materials.
Utilizing a feed stock which includes a typical polymer (polyethylene), changes in the chemical structure can be made through the various steps of this disclosure for obtaining a conjugated double bond system in the polymer chain.
The method of treatment disclosed has great advantage in intermediate step fluorination which prepares the polyethylene polymer or co-polymer system for subsequent treatment. By contrast with the present disclosure, it is possible to expose chlorinated polyethylene (CPE) with a strong base such as ethylenediamine (EDA) for many hours at ambient temperature with little or no reaction. This can be forced to yield a polymer which is altered in conductivity and which can therefore be described as a non-conductive material. By contrast, the present disclosure describes a dehydrohalogenation step which proceeds in quick order to ambient conditions. This disclosure sets forth a fluorine treatment which can then be dehydrohalogenated at room temperature in short order, perhaps a few minutes. Absent the fluorine treatment, the only way to force the conversion through dehydrohalogenation is to utilize excessive temperatures of perhaps 100.degree. C. or higher and much longer contact intervals with the EDA to accomplish dehydrohalogenation.
It is one object of the present procedure to therefore provide a preliminary step to assist in conducting the dehydrohalogenation step in the presence of a strong base (EDA is typical) and to obtain controllable surface penetration and controllable conversion to selected ranges of electrical conductivity.
Other advantages of the present procedure will become more readily apparent upon an evaluation of the process described hereinbelow. Moreover, a product is manufactured as will be described. Various examples of the method of manufacture are also set forth. In like fashion, specific tests describing the electrical conductivity are also included.